The present invention relates to water filters and relates more particularly to such a water filter which has a plunger fastened in the housing thereof and controlled by a lever to change the direction of an intake flow permitting it to be filtrated by a filter assembly or guided to a water outlet pipe directly, or causing it to wash or backwash said filter assembly.
Several water filter devices have been known and used in filtering city water. If a water filter is used in filtering city water, its filter element must be regularly cleaned or replaced so that a satisfactory filtering effect can be constantly obtained. However, it is not an easy job to wash or replace the filter element of a water filter. Further, while washing a water filter, the flow or washing water passes through the same water passage way as the filtrate does. Therefore, the flow of washing water which carries impurities out of the filter element may contaminate the piping of the water filter again.